Vice-president Joe Biden will lead a White House delegation to the Vatican for the investiture of Pope Francis that includes a Democrat, a Republican and a university president, it was confirmed Friday.

Biden, the highest ranking Roman Catholic in the Obama administration, will be accompanied by House minority leader Nancy Pelosi and Republican governor Susana Martinez of New Mexico.

Dr John DeGioia, the president of Georgetown University and a serving board member of the Association of Jesuit Colleges and Universities, will also join the group travelling to the Vatican for the March 19 inauguration mass celebrating the new pope.

Republican House speaker John Boehner, a Catholic, had initially been asked by the White House to attend. But he declined the invite, citing prior commitments.

In a statement earlier this week, Boehner said he was "grateful" for the invitation, but was unable to attend due to political duties that include hosting President Obama and the Irish taoiseach Enda Kenny in the House on Tuesday and debating the budget.

But Boehner said that he would send a bipartisan delegation from Congress to attend the investiture, led by New Jersey representative Chris Smith.

In line with a ban on the use of military aircraft by congressional members as part of moves to mitigate the effects of sequestration, the Washington group will be flying on a commercial plane.

Earlier this week, a Vatican spokesman, the Rev Tom Rosica, described the news that Biden would attend the inauguration mass as "significant". Asked if it would have been more appropriate for Obama to attend, Rosica said "it is not up to me to comment on anything like that".

The president is due to embark on a high-profile trip to the Middle East next week, including his first visit to Israel in office. The decision for him not to attend the Vatican means that preparations for that visit will not have to be altered.

But Obama has sent his best wishes to the new pope, describing him as a "champion of the poor and the most vulnerable among us".

He added in a statement Wednesday that followed the papal announcement that he looked forward to working with Pope Francis to "advance peace, security and dignity for our fellow human beings, regardless of their faith".